1. Technical Field
The present invention generally relates to wireless communication systems and in particular to control signaling in wireless communication systems.
2. Description of the Related Art
In current Worldwide Interoperability for Microwave Access (WiMAX) system implementations and the Institute of Electrical and Electronics Engineers (IEEE) 802.16e specifications, uplink sub-frame consists of control regions (for example, Channel Quality Indicator Channel (CQICH) and Hybrid Automatic Repeat Request Acknowledgement (HARQ ACK) regions) and data burst regions. Control regions take precedence over the data burst regions. In general, control regions occupy a small portion of the uplink sub-frame in order to maintain adequate uplink bandwidth for data transmission. However, because of the priority given to the control regions, in certain supported configurations, the available uplink bandwidth becomes so small that after the bandwidth is allocated for all control regions, there is not enough bandwidth for network entry messages.
Without network entry messages, a subscriber may be incapable of reporting the downlink channel quality information. Without this information, a base station access point media access control (MAC) layer may be unable to determine what modulation type to use on downlink data transfer for the subscriber. Consequently, some configurations are prevented from ever using these control region dominated systems. In particular, 5 MHz bandwidth and segmented partial usage of sub-carriers (PUSC) configurations are not compatible in systems in which the control region dominates the uplink bandwidth.